模拟微重力对猕猴肺组织结构及HSP70表达的影响

Effect of simulated microgravity on tissue structure and HSP70 expression in lungs of rhesus macaques

目的探讨模拟微重力状态对猕猴肺组织结构及热休克蛋白70(heat shock protein 70,HSP70)mRNA和蛋白表达的影响。方法采用国际通用方法,在特殊装置上采用猕猴头低位-10°模型模拟航天失重6周,将15只健康青壮年雄性猕猴随机分为3组:对照组(A)、失重组(B)和失重后恢复组(C)。用HE染色、透射电镜分别观察各组猕猴肺组织大体及超微结构的改变;免疫组化法观察HSP70在肺组织中的表达定位;实时荧光定量PCR(QPCR)、Western印迹法检测肺组织中HSP70 mRNA及蛋白水平的表达情况。结果与A组相比,B、C两组猕猴肺组织可见肺泡间隔增厚,部分肺泡融合,肺泡腔及间质内可见淋巴细胞浸润;超微结构改变主要表现为B、C两组可见肺泡上皮细胞核体积变小,形态不规则,胞质内板层小体数量增多、体积增大、排空加强,部分发生空泡样变;胞质内线粒体肿胀。免疫组化结果显示,各组肺组织支气管上皮细胞、血管内皮细胞及肺泡上皮细胞胞浆、胞核均表达HSP70;另外,B、C两组部分肺泡间质及肺泡腔渗出物内亦可见阳性信号。Q-PCR、Western印迹结果显示3组均可表达HSP70,组间差异无统计学意义(P>0.05)。结论中长期模拟微重力可引起猕猴肺组织损伤,但对肺组织HSP70 mRNA和蛋白的表达水平无明显影响。

Objective To investigate the effect of simulated microgravity on the tissue structure and the mRNA and pro- tein expression of HSP70 in lungs of rhesus macaques. Methods Fifteen healthy young male rhesus monkeys were randomly divided into 3 groups ： control group （ group A, n = 5 ）, 6 weeks＇simulated microgravity group （ group B, n = 5 ） and recovery for 4 weeks after 6 weeks of simulated mierogravity group （ group C, n = 5 ）. - 10 degree head-down-tih was used to simulate microgravity. HE staining and transmission electron microscopy were used to observe the histopathological and ultrastructural changes in pulmonary tissues. The expression and location of HSP70 in lung tissues were observed by immunohistoehemistry （IHC） method. The mRNA and protein expression of HSP70 in lung tissues were detected by quan- titative real-time PCR （Q-PCR）and Western blotting. Results Compared with group A, histopathological examination re- vealed alveolar septal thickening, partial fusion of pulmonary alveoli and alveolar and interstitial lymphocytic infiltration in groups B and C. Ultrastructure examination showed smaller and irregular nuclei of alveolar epithelial cells, an increased number and volume of the lamellar bodies, enhanced evacuation, part of vacuolar degeneration and mitochondrial swelling in groups B and C. IHC results showed that HSP70 was expressed in bronchial epithelial cells, vascular endothelial cells and alveolar epithelial cells of pulmonary tissues in each group, either in cytoplasm or in nucleus. In addition, the alveolar interstitial and alveolar exudates in groups B and C also showed positive signals. Q-PCR and Western blotting results showed that HSP70 was expressed in all of the three groups, but no significant difference was found between any two groups （ P 〉 0.05 ）. Conclusion Medium or long-term simulated mierogravity can cause damage to the lung tissue of rhesus mon- keys, but it has no effect on the expression of HSP70 in the lung tissue.